Exhaust gas generated from combusting an air/fuel mixture stored in a cylinder of an internal combustion engine is a heterogeneous mixture that contains gaseous carbon emissions such as, but not limited to, carbon monoxide (“CO”), unburned hydrocarbons and oxides of nitrogen (“NOx”) as well as particulate matter and soot comprising condensed phase materials (liquids and solids).
Vehicles typically include exhaust gas treatment systems that include one or more exhaust treatment devices such as, for example, a particulate filter. The particulate filter includes a filter substrate that is disposed in fluid communication with the exhaust gas. The filter substrate is configured to collect the particulate matter and soot as the exhaust gas flow therethrough.
Federally mandated engine output performance requirements are becoming stricter as concerns regarding carbon emissions continue to increase. Engine out soot models are typically used to estimate engine soot output, which in turn is used diagnose the in-use performance of an internal combustion engine and the particular filter. Conventional engine out soot models, however, may not estimate engine soot output with the accuracy needed to satisfy federally mandated in-use rate performance requirements. When operating an internal combustion engine in transient conditions, for example, conventional engine out soot models in combination with particular matter sensors can result in a false failing diagnosis or potentially false passing diagnosis.